This application claims priority of Taiwanese application no. 091209380, filed on Jun. 21, 2002.
1. Field of the Invention
The invention relates to a belt saw machine, more particularly to a belt saw machine with a rotatable cutter shield that can facilitate replacement of a belt cutter.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional belt saw machine 10 is shown to include a machine base 11 adapted to stand on a ground, a support frame unit 12 mounted on the machine base 11, a drive roller unit 13 mounted in the support frame unit 12, a belt cutter 14 trained on the drive roller unit 13, a workpiece positioning unit 15 mounted on the support frame unit 12 and movable vertically, and a cutter shield device 16 mounted on the support frame unit 12 for shielding the belt cutter 14. The belt saw machine 10 further includes a worktable 111 mounted horizontally on the machine base 11 and disposed in a notch 121 of the support frame unit 12. The drive roller unit 13 includes a motor 131 mounted fixedly on the support frame unit 12, a lower drive roller 132 mounted rotatably to the support frame unit 12 and driven by the motor 131, and an upper drive roller 133 mounted rotatably to the support frame unit 12. The belt cutter 14 is trained on the upper and lower drive rollers 133, 132, and extends through the worktable 111 in the notch 121. The workpiece positioning unit 15 includes a mounting block 151 secured to the support frame unit 12, a vertical rack 152 disposed between the mounting block 151 and the support frame unit 12, a rotatable adjusting rod 153 extending through the mounting block 151 in a direction transverse to the rack 152, a drive pinion 154 sleeved fixedly on the adjusting rod 153 for driving the rack 152, and a positioning block 155 mounted fixedly on a lower end of the rack 152. The cutter shield device 16 includes an angled shield plate 162 that is formed with a plurality of slots 1621, and a plurality of fasteners 161 that fasten a lower end of the shield plate 162 to the positioning block 155 through the slots 1621. When the fasteners 161 are tightly screwed, the shield plate 162 will be in a position for shielding the belt cutter 14. In use, the adjusting rod 153 is rotated to drive the rack 152 for moving the positioning block 155 downwardly until the latter presses a workpiece (not shown) against the worktable 111 for positioning the same. Thereafter, the motor 131 can be activated to drive the belt cutter 14 for cutting the workpiece. The cutter shield device 16 shields the belt cutter 14 for work safety. In practice, the conventional belt saw machine 10 suffers from the following drawbacks:
When replacing the belt cutter 14, since the shield plate 162 shields the belt cutter 14, the shield plate 162 must be dismantled, which requires unscrewing of the fasteners 161. Moreover, after replacing the belt cutter 14, the shield plate 162 has to be mounted once again on the positioning block 155 by tightly screwing the fasteners 161 through the slots 1621. Therefore, quick replacement of the belt cutter 14 is not possible in the conventional belt saw machine 10.
Therefore, the object of the present invention is to provide a belt saw machine with a rotatable cutter shield that can facilitate replacement of a belt cutter.
Accordingly, a belt saw machine of this invention comprises:
a machine base adapted to stand on a ground;
a support frame unit including a fixed cover mounted fixedly on the machine base, and a rotatable cover connected pivotally to the fixed cover and rotatable between a covering position and an open position;
a worktable mounted horizontally on the machine base and adapted to support the workpiece thereon;
a cutter unit including an upper drive roller mounted rotatably to the fixed cover, a lower drive roller mounted rotatably to an assembly of the machine base and the fixed cover, a motor mounted on the assembly of the machine base and the fixed cover for driving the lower drive roller, and an endless belt cutter trained on the upper and lower drive rollers and having a portion that extends through a space which is defined between the fixed cover and the rotatable cover when the rotatable cover is disposed at the covering position;
a workpiece positioning unit mounted on the fixed cover and disposed above the worktable, the workpiece positioning unit including a positioning block that is connected vertically and movably to the fixed cover and that is movable downwardly relative to the worktable so as to be adapted to press the workpiece against the worktable; and
a cutter shield device including
a vertical shield shaft having a lower end fixed on the positioning block, and
a shield assembly mounted on the shield shaft and pivotable thereabout, the shield assembly including an angled shield plate and a sleeve connected fixedly to the shield plate and sleeved rotatably on the shield shaft, the shield plate being confined between the fixed cover and the rotatable cover and having a lower portion projecting downwardly from the fixed cover and the rotatable cover for covering the belt cutter when the rotatable cover is disposed at the covering position, the shield plate being rotatable to a non-shielding position when the rotatable cover is disposed at the open position, thereby permitting replacement of the belt cutter.